密码屏蔽控制台应用程序

Question

我尝试了以下代码...

string pass = "";
Console.Write("Enter your password: ");
ConsoleKeyInfo key;

do
{
    key = Console.ReadKey(true);

    // Backspace Should Not Work
    if (key.Key != ConsoleKey.Backspace)
    {
        pass += key.KeyChar;
        Console.Write("*");
    }
    else
    {
        Console.Write("\b");
    }
}
// Stops Receving Keys Once Enter is Pressed
while (key.Key != ConsoleKey.Enter);

Console.WriteLine();
Console.WriteLine("The Password You entered is : " + pass);

但是这样输入密码时退格功能不起作用。 有什么建议吗？

Answer 1

Console.Write("\b \b"); 将从屏幕上删除星号字符，但您的 else 块中没有任何代码可以从 pass 字符串变量中删除先前输入的字符。

以下是应满足您要求的相关工作代码：

var pass = string.Empty;
ConsoleKey key;
do
{
    var keyInfo = Console.ReadKey(intercept: true);
    key = keyInfo.Key;

    if (key == ConsoleKey.Backspace && pass.Length > 0)
    {
        Console.Write("\b \b");
        pass = pass[0..^1];
    }
    else if (!char.IsControl(keyInfo.KeyChar))
    {
        Console.Write("*");
        pass += keyInfo.KeyChar;
    }
} while (key != ConsoleKey.Enter);

Answer 2

为此，您应该使用System.Security.SecureString

public SecureString GetPassword()
{
    var pwd = new SecureString();
    while (true)
    {
        ConsoleKeyInfo i = Console.ReadKey(true);
        if (i.Key == ConsoleKey.Enter)
        {
            break;
        }
        else if (i.Key == ConsoleKey.Backspace)
        {
            if (pwd.Length > 0)
            {
                pwd.RemoveAt(pwd.Length - 1);
                Console.Write("\b \b");
            }
        }
        else if (i.KeyChar != '\u0000' ) // KeyChar == '\u0000' if the key pressed does not correspond to a printable character, e.g. F1, Pause-Break, etc
        {
            pwd.AppendChar(i.KeyChar);
            Console.Write("*");
        }
    }
    return pwd;
}

Answer 3

完整的解决方案，原版 C# .net 3.5+

剪切和粘贴 :)

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    namespace ConsoleReadPasswords
    {
        class Program
        {
            static void Main(string[] args)
            {
                Console.Write("Password:");

                string password = Orb.App.Console.ReadPassword();

                Console.WriteLine("Sorry - I just can't keep a secret!");
                Console.WriteLine("Your password was:\n<Password>{0}</Password>", password);

                Console.ReadLine();
            }
        }
    }

    namespace Orb.App
    {
        /// <summary>
        /// Adds some nice help to the console. Static extension methods don't exist (probably for a good reason) so the next best thing is congruent naming.
        /// </summary>
        static public class Console
        {
            /// <summary>
            /// Like System.Console.ReadLine(), only with a mask.
            /// </summary>
            /// <param name="mask">a <c>char</c> representing your choice of console mask</param>
            /// <returns>the string the user typed in </returns>
            public static string ReadPassword(char mask)
            {
                const int ENTER = 13, BACKSP = 8, CTRLBACKSP = 127;
                int[] FILTERED = { 0, 27, 9, 10 /*, 32 space, if you care */ }; // const

                var pass = new Stack<char>();
                char chr = (char)0;

                while ((chr = System.Console.ReadKey(true).KeyChar) != ENTER)
                {
                    if (chr == BACKSP)
                    {
                        if (pass.Count > 0)
                        {
                            System.Console.Write("\b \b");
                            pass.Pop();
                        }
                    }
                    else if (chr == CTRLBACKSP)
                    {
                        while (pass.Count > 0)
                        {
                            System.Console.Write("\b \b");
                            pass.Pop();
                        }
                    }
                    else if (FILTERED.Count(x => chr == x) > 0) { }
                    else
                    {
                        pass.Push((char)chr);
                        System.Console.Write(mask);
                    }
                }

                System.Console.WriteLine();

                return new string(pass.Reverse().ToArray());
            }

            /// <summary>
            /// Like System.Console.ReadLine(), only with a mask.
            /// </summary>
            /// <returns>the string the user typed in </returns>
            public static string ReadPassword()
            {
                return Orb.App.Console.ReadPassword('*');
            }
        }
    }

Answer 4

取最上面的答案，以及来自它的cmets的建议，并修改它以使用SecureString而不是String，测试所有控制键，当密码长度时不会出错或在屏幕上多写一个“*”为0，我的解决办法是：

public static SecureString getPasswordFromConsole(String displayMessage) {
    SecureString pass = new SecureString();
    Console.Write(displayMessage);
    ConsoleKeyInfo key;

    do {
        key = Console.ReadKey(true);

        // Backspace Should Not Work
        if (!char.IsControl(key.KeyChar)) {
            pass.AppendChar(key.KeyChar);
            Console.Write("*");
        } else {
            if (key.Key == ConsoleKey.Backspace && pass.Length > 0) {
                pass.RemoveAt(pass.Length - 1);
                Console.Write("\b \b");
            }
        }
    }
    // Stops Receving Keys Once Enter is Pressed
    while (key.Key != ConsoleKey.Enter);
    return pass;
}

Answer 5

我的忽略控制字符并处理换行：

public static string ReadLineMasked(char mask = '*')
{
    var sb = new StringBuilder();
    ConsoleKeyInfo keyInfo;
    while ((keyInfo = Console.ReadKey(true)).Key != ConsoleKey.Enter)
    {
        if (!char.IsControl(keyInfo.KeyChar))
        {
            sb.Append(keyInfo.KeyChar);
            Console.Write(mask);
        }
        else if (keyInfo.Key == ConsoleKey.Backspace && sb.Length > 0)
        {
            sb.Remove(sb.Length - 1, 1);

            if (Console.CursorLeft == 0)
            {
                Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
                Console.Write(' ');
                Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
            }
            else Console.Write("\b \b");
        }
    }
    Console.WriteLine();
    return sb.ToString();
}

Answer 6

这会用红色方块掩盖密码，然后在输入密码后恢复为原始颜色。

它不会阻止用户使用复制/粘贴来获取密码，但如果它只是为了阻止别人偷看你的肩膀，这是一个很好的快速解决方案。

Console.Write("Password ");
ConsoleColor origBG = Console.BackgroundColor; // Store original values
ConsoleColor origFG = Console.ForegroundColor;

Console.BackgroundColor = ConsoleColor.Red; // Set the block colour (could be anything)
Console.ForegroundColor = ConsoleColor.Red;

string Password = Console.ReadLine(); // read the password

Console.BackgroundColor= origBG; // revert back to original
Console.ForegroundColor= origFG;

Answer 7

阅读控制台输入很困难，您需要处理特殊键，例如 Ctrl、Alt，以及光标键和 Backspace/Delete。在某些键盘布局上，例如Swedish Ctrl 甚至需要输入直接存在于美国键盘上的键。我相信尝试使用“低级”Console.ReadKey(true) 来处理这个问题非常困难，因此最简单和最可靠的方法是在输入密码期间使用一些 WINAPI 禁用“控制台输入回显”。

以下示例基于对Read a password from std::cin 问题的回答。

    private enum StdHandle
    {
        Input = -10,
        Output = -11,
        Error = -12,
    }

    private enum ConsoleMode
    {
        ENABLE_ECHO_INPUT = 4
    }

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern IntPtr GetStdHandle(StdHandle nStdHandle);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool GetConsoleMode(IntPtr hConsoleHandle, out int lpMode);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool SetConsoleMode(IntPtr hConsoleHandle, int dwMode);

    public static string ReadPassword()
    {
        IntPtr stdInputHandle = GetStdHandle(StdHandle.Input);
        if (stdInputHandle == IntPtr.Zero)
        {
            throw new InvalidOperationException("No console input");
        }

        int previousConsoleMode;
        if (!GetConsoleMode(stdInputHandle , out previousConsoleMode))
        {
            throw new Win32Exception(Marshal.GetLastWin32Error(), "Could not get console mode.");
        }

        // disable console input echo
        if (!SetConsoleMode(stdInputHandle , previousConsoleMode & ~(int)ConsoleMode.ENABLE_ECHO_INPUT))
        {
            throw new Win32Exception(Marshal.GetLastWin32Error(), "Could not disable console input echo.");
        }

        // just read the password using standard Console.ReadLine()
        string password = Console.ReadLine();

        // reset console mode to previous
        if (!SetConsoleMode(stdInputHandle , previousConsoleMode))
        {
            throw new Win32Exception(Marshal.GetLastWin32Error(), "Could not reset console mode.");
        }

        return password;
    }

Answer 8

我在 shermy 的 vanilla C# 3.5 .NET 解决方案中发现了一个错误，否则它很有魅力。我还在这里合并了 Damian Leszczyński - Vash 的 SecureString 想法，但如果您愿意，可以使用普通字符串。

错误：如果您在密码提示期间按退格键并且密码的当前长度为 0，则星号会错误地插入密码掩码中。要修复此错误，请修改以下方法。

    public static string ReadPassword(char mask)
    {
        const int ENTER = 13, BACKSP = 8, CTRLBACKSP = 127;
        int[] FILTERED = { 0, 27, 9, 10 /*, 32 space, if you care */ }; // const


        SecureString securePass = new SecureString();

        char chr = (char)0;

        while ((chr = System.Console.ReadKey(true).KeyChar) != ENTER)
        {
            if (((chr == BACKSP) || (chr == CTRLBACKSP)) 
                && (securePass.Length > 0))
            {
                System.Console.Write("\b \b");
                securePass.RemoveAt(securePass.Length - 1);

            }
            // Don't append * when length is 0 and backspace is selected
            else if (((chr == BACKSP) || (chr == CTRLBACKSP)) && (securePass.Length == 0))
            {
            }

            // Don't append when a filtered char is detected
            else if (FILTERED.Count(x => chr == x) > 0)
            {
            }

            // Append and write * mask
            else
            {
                securePass.AppendChar(chr);
                System.Console.Write(mask);
            }
        }

        System.Console.WriteLine();
        IntPtr ptr = new IntPtr();
        ptr = Marshal.SecureStringToBSTR(securePass);
        string plainPass = Marshal.PtrToStringBSTR(ptr);
        Marshal.ZeroFreeBSTR(ptr);
        return plainPass;
    }

Answer 9

这是一个增加了对Escape 键（返回null 字符串）支持的版本

public static string ReadPassword()
{
    string password = "";
    while (true)
    {
        ConsoleKeyInfo key = Console.ReadKey(true);
        switch (key.Key)
        {
            case ConsoleKey.Escape:
                return null;
            case ConsoleKey.Enter:
                return password;
            case ConsoleKey.Backspace:
                if (password.Length > 0) 
                {
                    password = password.Substring(0, (password.Length - 1));
                    Console.Write("\b \b");
                }
                break;
            default:
                password += key.KeyChar;
                Console.Write("*");
                break;
        }
    }
}

Answer 10

（我的）nuget package 这样做，基于最佳答案：

install-package PanoramicData.ConsoleExtensions

用法：

using PanoramicData.ConsoleExtensions;

...

Console.Write("Password: ");
var password = ConsolePlus.ReadPassword();
Console.WriteLine();

项目网址：https://github.com/panoramicdata/PanoramicData.ConsoleExtensions

欢迎拉取请求。

Answer 11

您可以将您的密钥附加到一个累积的链表中。

收到退格键后，从列表中删除最后一个键。

收到回车键后，将列表折叠成一个字符串，然后完成剩下的工作。

Answer 12

我对退格做了一些更改

        string pass = "";
        Console.Write("Enter your password: ");
        ConsoleKeyInfo key;

        do
        {
            key = Console.ReadKey(true);

            // Backspace Should Not Work
            if (key.Key != ConsoleKey.Backspace)
            {
                pass += key.KeyChar;
                Console.Write("*");
            }
            else
            {
                pass = pass.Remove(pass.Length - 1);
                Console.Write("\b \b");
            }
        }
        // Stops Receving Keys Once Enter is Pressed
        while (key.Key != ConsoleKey.Enter);

        Console.WriteLine();
        Console.WriteLine("The Password You entered is : " + pass);

Answer 13

我已经更新了 Ronnie 的版本，因为我花了 太多时间 尝试输入密码，却发现我的 CAPS LOCK 已打开！

在此版本中，_CapsLockMessage 中的任何消息都将“浮动”在输入区域的末尾并以红色显示。

此版本需要更多代码，并且确实需要轮询循环。在我的计算机上，CPU 使用率约为 3% 到 4%，但如果需要，可以随时添加一个小的 Sleep() 值来降低 CPU 使用率。

    private const string _CapsLockMessage = " CAPS LOCK";

    /// <summary>
    /// Like System.Console.ReadLine(), only with a mask.
    /// </summary>
    /// <param name="mask">a <c>char</c> representing your choice of console mask</param>
    /// <returns>the string the user typed in</returns>
    public static string ReadLineMasked(char mask = '*')
    {
        // Taken from http://stackoverflow.com/a/19770778/486660
        var consoleLine = new StringBuilder();
        ConsoleKeyInfo keyInfo;
        bool isDone;
        bool isAlreadyLocked;
        bool isCapsLockOn;
        int cursorLeft;
        int cursorTop;
        ConsoleColor originalForegroundColor;

        isDone = false;
        isAlreadyLocked = Console.CapsLock;

        while (isDone == false)
        {
            isCapsLockOn = Console.CapsLock;
            if (isCapsLockOn != isAlreadyLocked)
            {
                if (isCapsLockOn)
                {
                    cursorLeft = Console.CursorLeft;
                    cursorTop = Console.CursorTop;
                    originalForegroundColor = Console.ForegroundColor;
                    Console.ForegroundColor = ConsoleColor.Red;
                    Console.Write("{0}", _CapsLockMessage);
                    Console.SetCursorPosition(cursorLeft, cursorTop);
                    Console.ForegroundColor = originalForegroundColor;
                }
                else
                {
                    cursorLeft = Console.CursorLeft;
                    cursorTop = Console.CursorTop;
                    Console.Write("{0}", string.Empty.PadRight(_CapsLockMessage.Length));
                    Console.SetCursorPosition(cursorLeft, cursorTop);
                }
                isAlreadyLocked = isCapsLockOn;
            }

            if (Console.KeyAvailable)
            {
                keyInfo = Console.ReadKey(intercept: true);

                if (keyInfo.Key == ConsoleKey.Enter)
                {
                    isDone = true;
                    continue;
                }

                if (!char.IsControl(keyInfo.KeyChar))
                {
                    consoleLine.Append(keyInfo.KeyChar);
                    Console.Write(mask);
                }
                else if (keyInfo.Key == ConsoleKey.Backspace && consoleLine.Length > 0)
                {
                    consoleLine.Remove(consoleLine.Length - 1, 1);

                    if (Console.CursorLeft == 0)
                    {
                        Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
                        Console.Write(' ');
                        Console.SetCursorPosition(Console.BufferWidth - 1, Console.CursorTop - 1);
                    }
                    else
                    {
                        Console.Write("\b \b");
                    }
                }

                if (isCapsLockOn)
                {
                    cursorLeft = Console.CursorLeft;
                    cursorTop = Console.CursorTop;
                    originalForegroundColor = Console.ForegroundColor;
                    Console.ForegroundColor = ConsoleColor.Red;
                    Console.Write("{0}", _CapsLockMessage);
                    Console.CursorLeft = cursorLeft;
                    Console.CursorTop = cursorTop;
                    Console.ForegroundColor = originalForegroundColor;
                }
            }
        }

        Console.WriteLine();

        return consoleLine.ToString();
    }

Answer 14

这是我的简单版本。 每次按下一个键，从控制台中删除所有内容，并绘制与密码字符串长度一样多的“*”。

int chr = 0;
string pass = "";
const int ENTER = 13;
const int BS = 8;

do
{
   chr = Console.ReadKey().KeyChar;
   Console.Clear(); //imediately clear the char you printed

   //if the char is not 'return' or 'backspace' add it to pass string
   if (chr != ENTER && chr != BS) pass += (char)chr;

   //if you hit backspace remove last char from pass string
   if (chr == BS) pass = pass.Remove(pass.Length-1, 1);

   for (int i = 0; i < pass.Length; i++)
   {
      Console.Write('*');
   }
} 
 while (chr != ENTER);

Console.Write("\n");
Console.Write(pass);

Console.Read(); //just to see the pass

Answer 15

天哪

    static string ReadPasswordLine()
    {
        string pass = "";
        ConsoleKeyInfo key;
        do
        {
            key = Console.ReadKey(true);
            if (key.Key != ConsoleKey.Enter)
            {
                if (!(key.KeyChar < ' '))
                {
                    pass += key.KeyChar;
                    Console.Write("*");
                }
                else if (key.Key == ConsoleKey.Backspace && pass.Length > 0)
                {
                    Console.Write(Convert.ToChar(ConsoleKey.Backspace));
                    pass = pass.Remove(pass.Length - 1);
                    Console.Write(" ");
                    Console.Write(Convert.ToChar(ConsoleKey.Backspace));
                }
            }
        } while (key.Key != ConsoleKey.Enter);
        return pass;
    }

Answer 16

如果我理解正确，您是在尝试让退格键同时删除屏幕上可见的 * 字符和 pass 变量中的缓存字符？

如果是这样，那么只需将您的 else 块更改为：

            else
            {
                Console.Write("\b");
                pass = pass.Remove(pass.Length -1);
            }

Answer 17

 string pass = "";
 Console.WriteLine("Enter your password: ");
 ConsoleKeyInfo key;

 do {
  key = Console.ReadKey(true);

  if (key.Key != ConsoleKey.Backspace) {
   pass += key.KeyChar;
   Console.Write("*");
  } else {
   Console.Write("\b \b");
   char[] pas = pass.ToCharArray();
   string temp = "";
   for (int i = 0; i < pass.Length - 1; i++) {
    temp += pas[i];
   }
   pass = temp;
  }
 }
 // Stops Receving Keys Once Enter is Pressed
 while (key.Key != ConsoleKey.Enter);

 Console.WriteLine();
 Console.WriteLine("The Password You entered is : " + pass);